Synthesize up to five gram quantities of iron (III) chelating agents which are capable of promoting the excretion of excess iron from persons suffering from iron overload. The chelating agents will primarily be hexadentate, and will be designed on the basis of currently available biological data and knowledge of the stability of iron (III) complexes, taking into account in vivo interferences, e.g., plasma pH and competing endogenous metals and ligands. The chelating agents will belong to the following classes: derivatives of N,N'-bis(2-hydroxyphenyl)ethylenediamine-N,N'-diacetic acid and related structures; spherands and crowns containing the hydroxymetaphenylene part structure; tripodal chelators containing tropolone, oxine, thiosemicarbazone, and hydroxamate groups; and phenolic derivatives of amino carboxylic and phosphonic acids. In vitro screens will be used to determine the ability of certain of the chelators to remove iron from ferritin and transferrin.